SB-242084

SB-242084 is a selective antagonist of the serotonin 5-HT_2C receptor which is used in scientific research.

It has anxiolytic effects-like effects in rodents, and enhances dopamine signalling in the limbic system, as well as having complex effects on the dopamine release produced by cocaine, increasing it in some brain regions but reducing it in others. In animal studies, SB-242084 produced stimulant-type activity and reinforcing effects, somewhat similar to but much weaker than cocaine or amphetamines. It is self-administered by monkeys. It has been found to increase dopamine levels in the striatum in rats and in the nucleus accumbens in monkeys by about 200%.

The drug has been shown to increase the effectiveness of the selective serotonin reuptake inhibitor (SSRI) class of antidepressants in animals, and may also reduce their side effects. SSRIs acutely reduce social interaction in rodents, thought to be an anxiogenic response, and this effect can be reversed by SB-242084. In addition, SSRIs have been found to acutely induce hypolocomotion, which can be reversed by SB-242084.

SB-242084 was under development by GlaxoSmithKline for the treatment of anxiety disorders in the late 1990s. However, its development looks to have been abandoned.